ecology

Question 1

definition of ecosystem?

Answer 1

a described system or area where organisms interact with their physical environment

Question 2

definition of population?

Answer 2

the total number of individuals of one species in a particular place at a particular time

Question 3

definition of habitat?

Answer 3

these are specific places were specific organisms live

Question 4

definition of community?

Answer 4

is formed of the populations of all species present in an ecosystem at a particular time

Question 5

to measure population size we?

Answer 5

place a quadrat on the ground
count the number of individuals of our chosen species inside of the square

Question 6

how do we take an estimate percentage of a population size?

Answer 6

-calculate area of habitat
-use random sampling to place a quadrat (random number generator)
-place quadrat and repeat 10x to make results reliable
-calculate average number of individuals in a quadrat
-calculate how many quadrats fit into total area
-then multiply steps 4 and 5

Question 7

definition of biodiversity?

Answer 7

measure of the variety of living organisms within a particular habitat or ecosystem

Question 8

investigate the distribution of organisms in their habitat?

Answer 8

-pick 2 contrasting areas and place a grid in each
-use random sampling to take repeated measurements using a quadrat
-compare average result
-use a transect
-to measure the number of % cover of species

Question 9

what is the difference between biotic and abiotic factors?

Answer 9

abiotic is non-living and biotic is living

Question 10

examples of abiotic factors?

Answer 10

sunlight
temperature
water
humidity
wind
space
pollution
soil type

Question 11

examples of biotic factors?

Answer 11

human activity
predatation
competition
food availability

Question 12

name all the trophic levels in order with examples?

Answer 12

producer-grass
primary consumer- grasshopper
secondary consumer- bird
tertiary consumer- snake
top carnivore-hawk

Question 13

definition of trophic level?

Answer 13

the feeding level in a food chain

Question 14

definition of producer?

Answer 14

organisms that make their own food using small molecules and energy from the sun

Question 15

definition of primary consumer?

Answer 15

eats the producer

Question 16

definition of secondary consumer?

Answer 16

found in the third trophic level and eats the primary consumer

Question 17

definition of tertiary consumer?

Answer 17

4th trophic level and relies on other things for food and eats the secondary consumer

Question 18

definition of top carnivore?

Answer 18

the animal occupying the uppermost trophic level in a food chain or web. It is not eaten by another organism whilst alive.

Question 19

definition of biomass?

Answer 19

the total mass of living material in an organism or trophic level

Question 20

definition of decomposer?

Answer 20

organisms (fungi or bacteria) which digest the remains of dead organisms via saprotrophic feeding. This process releases minerals into the soil.

Question 21

which is better of food webs or chains and why?

Answer 21

webs as you can see the whole and true picture/ecosystem and see many different directions and multiple food chains

Question 22

disadvantages of a food web?

Answer 22

can be confusing and can’t put in decomposers

Question 23

what do the arrows show in a food web or chain?

Answer 23

direction of energy transfer

Question 24

what is a pyramid of number?

Answer 24

a diagram which shows the numbers, drawn to scale, of living organisms at each level in a food chain

Question 25

what is a pyramid of biomass?

Answer 25

plant/animal matter that is used as an energy store

Question 26

what is a pyramid of energy?

Answer 26

biologists express the energy available at a trophic level in a particular area as kilojoules per square meter per year

Question 27

what nutrients are transferred from one trophic level to the next?

Answer 27

carbon, nitrogen and glucose

Question 28

how much energy is transferred from one trophic level to the next?

Answer 28

10%

Question 29

give reasons why energy is lost from sun to producer?

Answer 29

-some light will miss the plant or plants chloroplasts
-some light will be reflected by the cuticle
-some light will be the wrong wavelength and not be absorbed

Question 30

gives reasons why energy is lost from consumer to consumer?

Answer 30

-not all material is consumed
-not all material is digested- some egested as faeces
-respiration-lost as heat
-used for growth
-excretion (urine)

Question 31

how to calculate energy lost?

Answer 31

energy transferred to next trophic level/energy received during transfer X100

Question 32

why do plants need nitrogen?

Answer 32

to make amino acids, proteins, nucleic acid- to make DNA/RNA and for growth

Question 33

where are decomposers found and what do they do in the nitrogen cycle?

Answer 33

stage decomposition- micro-organisms convert detritus and waste products to ammonia

Question 34

where are nitrifying bacteria found and what do they do in the nitrogen cycle?

Answer 34

stage nitrogen fixation- conversion of nitrogen gas into ammonia in soil and root nodules

stage nitrification- conversion of ammonia to nitrites and then nitrites to nitrates

Question 35

where are denitrifying bacteria found and what do they do in the nitrogen cycle?

Answer 35

stage denitrification and nitrates are used as an energy source, releasing nitrogen gas onto the atmosphere